#include<sys/types.h>
#include<sys/socket.h>

#include<netinet/in.h>
#include<arpa/inet.h>

#include<netdb.h>
#include<string.h>
#include<stdlib.h>

#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff
#endif

extern errno;

int errexit(const char *format, ...);

int
connectsock(const char *host, const char *service, const char *transport)
{
	struct hostent *phe;
	struct servent *pse;
	struct protoent *ppe;
	struct sockaddr_in sin;

	int s, type;

	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;

	if ( pse = getservbyname(service, transport) )
		sin.sin_port = pse->s_port;
	else if ( (sin.sin_port = htons((unsigned short)atoi(service))) == 0 )
		errexit( "can't get \"%s\" service entry\n", service);

	if ( phe = gethostbyname(host) )
		memcpy(&sin.sin_addr, phe->h_addr, phe->h_length);
	else if ( (sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE)
		errexit("can't get \"%s\" host entry\n", host);

	if ( (ppe = getprotobyname(transport)) == 0 )
		errexit("can't get \"%s\" protocol entry\n", transport);

	if (strcmp(transport, "udp") == 0)
		type = SOCK_DGRAM;
	else 
		type = SOCK_STREAM;

	s = socket(PF_INET, type, ppe->p_proto);

	if (s < 0)
		errexit("can't create socket: %s\n", strerror(errno));

	if (connect( s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
		errexit( "can't connect to %s.%s: %s\n", host, service,
				transport);

	return s;

}
